Re: [PATCH] mm/rmap: remove stale hugetlb check in try_to_unmap_one

[Kunwu Chan]

On Mon, 31 Aug 2026 08:28:47 +0000 Dev Jain <dev.jain@xxxxxxx> wrote:

> Post commit d4ec5572825a ("mm/rmap: add try_to_unmap_poisoned_hugetlb_one")
> try_to_unmap_one() cannot be called with a hugetlb folio. Therefore remove
> the folio_test_hugetlb() check.

Yes, the d4ec5572825 change shows that try_to_unmap() dispatches 
hugetlb folios to try_to_unmap_poisoned_hugetlb_one(), 
so try_to_unmap_one() cannot be called with a hugetlb folio.


It would be better to add:
Fixes: d4ec5572825 ("mm/rmap: add try_to_unmap_poisoned_hugetlb_one")

Reviewed-by: Kunwu Chan <kunwu.chan@xxxxxxxxx>

Thanks,
KunWu

> 
> Signed-off-by: Dev Jain <dev.jain@xxxxxxx>
> ---
> Rebase soup - my huge_ptep_get() fixes landed after the refactoring.
> 
> This patch applies on Linux 7.3-rc1.
> 
>  mm/rmap.c | 7 ++-----
>  1 file changed, 2 insertions(+), 5 deletions(-)
> 
> diff --git a/mm/rmap.c b/mm/rmap.c
> index d1819fd699380..606c8ecf31302 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -2299,11 +2299,8 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
>  		VM_BUG_ON_FOLIO(!pvmw.pte, folio);
>  
>  		address = pvmw.address;
> -		if (folio_test_hugetlb(folio)) {
> -			pteval = huge_ptep_get(mm, address, pvmw.pte);
> -		} else {
> -			pteval = ptep_get(pvmw.pte);
> -		}
> +		pteval = ptep_get(pvmw.pte);
> +
>  		if (likely(pte_present(pteval))) {
>  			pfn = pte_pfn(pteval);
>  		} else {
> -- 
> 2.43.0
> 
>